Composition for coating surfaces of iron and steel.



ROBERT S. PERRY, OF CAVE SPRING, GEORGIA.

COMPOSITION non COATING SURFACES or mow Ann srnnn No Drawing.

taining a mineral hydrocarbon base, in conjunction with a chromium salt of the character and in the condition hereinafter set forth, and its purpose is to prevent or minimize rusting of the iron or steel.

To prepare my surfacer, I preferably take refined asphalt, and ,heat it to a temperature at which it becomes quite fluid, say at about- 200 Fahrenheit. I then diffuse throughout the liquefied asphalt, a water-soluble, or

partly watersoluble salt of chromium, in a comminuted and substantially dry condition; that is to say, said salt isemployed Without water (other than its water of crystallization, if it be employed in crystalline form), and without the use of any ve- "constitutes my invention.

hicle containingaqueous moisture, in the initial formation of the compound which The salt is introduced without the introduction or employment of any substantial amount of water in the form of a ueous moisture, in order to maintain the ful value of a protective coating, which shall be durable and shall be a good 'excluder of moisture and other agency ofmetal decay, but the water of crystallization in a chromium salt does not impair the essential function of said salt in the ultimate compound, and hence for.

the purposes of the present description, the term substantially dry, is properly appli-' cable to the salt under these conditions. I prefer to use for this purpose, bichromate of soda, but the. normal chromate of soda or potash may, be-em loyed. Where the bichromate is used, goo results may be obtained by adding two and one-half per cent. thereof, but this amount may be varied, and in some instances as high a proportion as twenty per cent. may be found desirable.

' This salt may be introduced either in a crystalline form, or in a'state of subdivision Specification of Letters Patent. Application filed March 17, 1913. Serial No. 754,815.

fine enough for complete and ready difiu' sion, or it may be desiccated and comminuted. f i

The ultimate productshould, of course,

Patented July 2?, i915.

not contain an injurious quantity of any substance which'would tend to stimulate COI'I'OSIOH of the iron or steel, such for instance as the metals which are electro-negative to iron, and hence I use the'term subs'tantially free from rust stimulating substances, as fairly descriptive of the proper characteristic. The compound thus formed'may; be allowed to cool, for convenience of handling,

and may be usedalone, by reheating, or in conjunction with any suitable vehicle not containing rust-stimulating substances. Its

intended purpose is as a surfacer for iron or steel, whether applied as a coating by means of a brush or other distributing means, or by dipping. A

Instead of asphalt any other suitable mineral hydrocarbon base, such as coal tar,

paraffin, or any bitumen or pyrobitumen,

which is suiiiciently viscous to adapt it to' be used as a surfacer, and which is substan'-- tially free from rust-stimulating ingredients, may be employed in conjunction with the chromic salt. an appropriate one to indicate the spreading quality, adhesiveness and tenacity which are characteristic of the above mentioned mineral hydrocarbons when heated, or employed in conjunction with a suitable flux or vehicle.

I-believe that the rust-inhibiting qualities of the above described surfacer, are largely due to the fact that the chromiumsalt, being very completely diffused, in a comminuted condition, throughout the bituminous material, is primarily accessible to any water or aqueous moisture which penetrates the latter, and, being water-soluble, or partly water-soluble, it is taken up by the water or moisture, sufliciently to be carried 'along use the term viscous as with it, to any point of contact with the iron or steel, which may be attained by the water or moisture. Thus the antidote to rust is directly presented at the region where its action is needed, by meansof thewater or aqueous moisture, which would otherwise tend to produce corrosion. It must be un derstood, however, that I do-not intend to make the above mentioned theory ,'a part of the essence of my invention, but slmp'ly pre- I sent it as a possible explanation of the .rust-.

inhibiting action, which I have found to occur.

Having thus described my invention, I claim:

1. The hereinbefore described surfacer, consisting of a substantially viscous hydrocarbon base in'co'njunction with a chromic salt,

' being substantially free from rust-stimulatdiflu sed therethrough in a comminuted and substantially dry condition, said compound ing substances.

2. The hereinbefore described surfacer, con-' 1 In testimony whereof, I

signed my name at Philadelphia, Pennsyl- Vania, this fifth dayof March 1913.

ROBERT S. PERRY.

Witnesses: f

JAMES H. BE'LL, I E. L. FULLERTON. 

